【AT32F421 Review】+ Display driver for OLED screen

jinglixixi

【AT32F421 Review】+ Display driver for OLED screen [Copy link]

 

 

The AT32F421 development board is equipped with an Arduino interface, which greatly facilitates the expansion of peripherals and functions. For example, we can use its I2C interface to drive the display of the OLED screen, and the display effect is shown in the figure.

Since the I2C interface on the board is misaligned with the pin connection of the OLED screen, the problem can be solved in minutes by using GPIO to simulate I2C.

OLED screen display effect

The connection relationship between the OLED screen and the MCU is:

SCL---PB9

SDA--PB8

The relevant definition statements for the pin output high and low levels are as follows:

#define OLED_SCLK_Set() GPIOB->BSRE = GPIO_Pins_9

#define OLED_SCLK_Clr() GPIOB->BRE = GPIO_Pins_9

#define OLED_SDIN_Set() GPIOB->BSRE = GPIO_Pins_8

#define OLED_SDIN_Clr() GPIOB->BRE = GPIO_Pins_8

The pin output function setting function of the OLED screen is:

void AT32_OLED_Init(void)
{
 GPIO_InitType GPIO_InitStructure;
 RCC_AHBPeriphClockCmd(RCC_AHBPERIPH_GPIOB, ENABLE);
 GPIO_StructInit(&GPIO_InitStructure);
 GPIO_InitStructure.GPIO_Pins = GPIO_Pins_8|GPIO_Pins_9;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
 GPIO_InitStructure.GPIO_OutType = GPIO_OutType_PP;
 GPIO_InitStructure.GPIO_Pull = GPIO_Pull_NOPULL;
 GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;
 GPIO_Init(GPIOB, &GPIO_InitStructure);
}

The corresponding string output function is:

void OLED_ShowCHinese(uint8_t x, uint8_t y, uint8_t no)
{
 uint8_t t,adder=0;
 OLED_Set_Pos(x,y);
 for(t=0;t<16;t++)
 {
 OLED_WR_Byte(Hzk[2*no][t],OLED_DATA);
 adder+=1;
 }
 OLED_Set_Pos(x,y+1);
 for(t=0;t<16;t++)
 {
 OLED_WR_Byte(Hzk[2*no+1][t],OLED_DATA);
 adder+=1;
 }
}

The main program to realize string display is:

int main(void)
{
 AT32_Board_Init();
 AT32_OLED_Init();
 OLED_Init();
 OLED_Clear();
 OLED_ShowString(0,0,"AT32F421 TEST",16);
 OLED_ShowString(0,2,"OLED DISPLAY",16);
 for(;;)
 {
 AT32_LEDn_Toggle(LED2);
 Delay_ms(200);
 AT32_LEDn_Toggle(LED3);
 Delay_ms(200);
 AT32_LEDn_Toggle(LED4);
 Delay_ms(200);
}
}

soso

Good, it seems that the Arduino interface is necessary.

jinglixixi

soso posted on 2021-4-12 09:30 Good, it seems that the Arduino interface is necessary.

Yes, it works well with peripherals.

bqgup

Can the display be displayed vertically? Like a bracelet display

jinglixixi

bqgup posted on 2021-4-12 11:35 Can the display screen be displayed vertically? Like the display of a bracelet

This should be no problem, just transpose the font display.

w494143467

Not bad, IIC driver is really good~

freebsder

Thank you for sharing. I2C is not complicated and is a must-have project for practice.

Jacktang

The pin connection between the I2C interface and the OLED screen is misaligned

Is it a small mistake in the board design?

Albert.G

I heard that the IIC of STM32 has some problems. I don't know how it works for Arteli. Has the OP encountered this?

jinglixixi

Jacktang posted on 2021-4-12 22:44 Is the misalignment of the pin connection between the I2C interface and the OLED screen a small mistake in the board design?

This is not the case. It is mainly because the pin arrangement of the OLED screen is not very suitable for the characteristics of the Arduino interface.

jinglixixi

Albert.G posted on 2021-4-13 08:41 I heard that STM32's own IIC has some problems. I wonder how it works for Arteli. Has the OP encountered this?

For the convenience of using pins, I seldom use hardware I2C to drive peripherals directly. It’s just that the usage habits are different, but it’s good as long as I can realize the functions I need.

jinglixixi

freebsder posted on 2021-4-12 22:41 Thank you for sharing. I2C is not complicated and is a must-have project for practice.

Yes, the use of gadgets like OLED screen is the second only to LED lighting as a GPIO port testing method, but it is more powerful than LED.

jinglixixi

w494143467 posted on 2021-4-12 16:28 Not bad, IIC driver is really good~

Yes, it only uses one more pin than LED, but its information expression is much stronger.

dql2016

jinglixixi

dql2016 posted on 2021-4-13 17:02